THIS INVENTION relates to a safety device, and more particularly relates to a safety device in a motor vehicle such as a motor car.
When a motor vehicle is involved in an accident there is a risk that the driver and passengers within the vehicle will be injured. It has been proposed to provide vehicles with safety devices to reduce the risk of such injury.
Certain safety devices are intended to provide protection in the case of a side impact. U.S. Pat. No. 5,322,322 discloses such a device. An inflatable tube is initially stored in a recess in the door frame above the door of the vehicle, and the ends of the tube are pivotally anchored to fixed points on the door frame. A sensor is provided to sense when an accident occurs, and to initiate inflation of the tube. As the tube inflates its length decreases, and it then extends linearly between the two fixed points on the door frame. The inflated tube provides some protection for the head of a person sitting in the vehicle However, the tube is inflated to a substantial pressure, and thus the head of a person in the vehicle may tend to bounce off the tube. The tube may not cover the whole of the area of the window, and may not even cover the whole of the upper part of the window. There is thus a risk that the head of the person in the vehicle may move past the tube and pass through the window opening. If a car is rolling over this is very undesirable.
This invention seeks to provide an improved safety device.
According to this invention there is provided a safety device in a motor vehicle, the device comprising a gas generator, incorporating or associated with a sensor adapted to sense a side impact or a roll-over and to activate the gas generator, and an inflatable element connected to the gas generator to be inflated by gas from the gas generator, the inflatable element being made of fabric comprising a first layer to define the front part of the inflatable element, and a second layer to define the back part of the inflatable element, selected parts of the first layer and the second layer being interconnected to define points or lines where the front part and back part of the inflatable element are secured together, the inflatable element incorporating a plurality of substantially parallel elongate cells, the inflatable element having an edge portion secured to part of the door frame of the vehicle, which is non-linear, the inflatable element, when inflated, being positioned adjacent the door contained within the door frame.
The inflatable element, when inflated, is thus located between the head of a person sitting in the vehicle and an adjacent door. Usually such a door is provided with a window and so the inflated element provides protection from breaking glass from the window, and also prevents the head of the person in the vehicle from striking the window, or from being thrown out through the window, as can happen, particularly with roll-over accidents.
Preferably the safety device is usually initially stored in a recess provided in the doorframe.
Preferably the inflatable element is made of interwoven fabric layers, the selected parts of the first layer and the second layer being interwoven. Preferably there is internal venting between the cells as this may reduce undesirable bounce that might occur if the cells were discrete and not vented to each other.
The cells may be immediately adjacent each other or may be spaced apart. At least some of the cells may be of conical form when inflated.
The inflatable element may be formed of a fabric with parts of the fabric being interwoven to form the cell or cells. The fabric may have a single layer weight of less than 300 g/sq m, such as a weight of 175 g/sq m.
Preferably when the inflatable element is inflated the pressure of gas is approximately 3 bar. Preferably the inflatable element, when inflated, extends past the B-post of the vehicle, to provide protection for the head of the driver. If the head of the driver should impact with the B-post in an accident the consequences could be fatal.
In one embodiment the inflatable element incorporates a strap to connect part of the inflatable element to the door frame. The strap is tight, that is, tensioned to a significant extent, when the inflatable element is inflated.
Separate means may be provided to apply tension to part of the inflatable element when it is inflated, such as a piston and cylinder, adapted to be moved by gas from a gas generator when the inflatable element is inflated, to apply tension to one edge of the inflatable element, to hold the inflated element in a desired position.
In one embodiment the inflatable element is provided with means adapted to move from an initial position to a further position on inflation of the inflatable element, an arrangement being provided to retain the means in the further position. Thus, a slider may be provided adapted to slide along a ratchet, and to be retained by the ratchet when it has moved to a further position.